/*
package NiuKe;

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

*/
/**
 * @Description:
 * @Author: Hanzao
 * @Date: 2022/06/12/21:32
 *//*

public class HJ10 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        Set set = new HashSet();
        for(int i=0;i<s.length();i++){
            set.add(s.charAt(i));
        }
        System.out.println(set.size());
    }
}
*/
